Work feeding mechanism for sewing machines



Feb. 16, 1954 R HAYES WORK FEEDING MECHANISM FOR SEWING MACHINES 4 Sheets-Sheet 1 Filed Dec.

IN V EN TOR.

B ROBERIT A. HAYES AT rg NEY Feb. 16, 1954 R. A. HAYES WORK FEEDING MECHANISM FOR SEWING MACHINES 4 Sheets-Sheet 2 Filed Dec. 19, 1951 ROBERT A. HAY'ES ATTORNEY H Feb. 16, 1954 R. A. HAYES WORK FEEDING MECHANISM FOR SEWING MACHINES Filed Dec. 19} 195 1 4 Sheets-Sheet 3 IN VEN TOR.

ROBERT A. HAYES ATTORNEY Feb. 16, 1954 R. A. HAYES WORK FEEDING MECHANISM F OR SEWING MACHINES Filed Dec 19, 1951 4 Sheets-Sheet 4 INVENTUR,

BY ROBERT A. HAYES 7* C W ATTORNEY Patented Feb. 16, 1954 WORK FEEDING MECHANISM FOR SEWING 1 MACHINES,

Robert A. Hayes, Franklin Park, Ill., assignor to Union Special Machine Company, Chicago, III., a corporation of Illinois Application December 19, 1951, Serial No. 262,407

8 Claims. (Cl. 112-209) This invention relates to sewing machines and, more particularly, to work-feeding mechanisms therefor. It has special reference to work-feeding mechanisms embodying a plurality of fourmotion feed dogs having a differential action in relation to each other.

In the performance of various seaming operations, as, in the seaming of rather easily stretchablefabrics, it has been recognized as desirable to employ a plurality of feed dogs, i. e., a main feed dog and an auxiliary feed dog, in tandem relation, these being arranged to impart different extents of feed to the work in advance of and to the rear of the point of stitch formation. Provision is frequently made for the adjustment of the relative movement of the feed dogs so arranged in tandem.

A primary object of the present invention is the provision in a sewing machine of means for simultaneously varying the feed stroke of a plu-v rality of differentially operable feed dogs at the will of the operator while the machine is in operation. The arrangement contemplated is such that the change in feed stroke is accomplished without varying the ratio of the feed strokes of the several feed dogs so that the ratio determined as best suited for the particular work being performed is not disturbed. I

Various purposes are served by this simultaneous change of the stroke of a plurality of feed dogs without interruption of the operation of the machine and without varying the relationshipof the feeding actions of the feed dogs. By way of example, it permits the firm attachment of the end of an elastic strip across which a seam is being formed. Thus, if a seam is being formed, across a. relatively narrow elastic strip which would normally provide only fouror five stitches across the strip, the action of a plurality of feed dogs may be varied simultaneously in passing acrossthe strip, without interrupting the operation of the machine, to provide twenty' or more stitchesacross the strip to firmly anchor the same; So also, an effect similar to a, tacking operation may be performed at the beginning or end "of a seam, or both, by greatly shortening the H 2 Thus, regardless of the preferred ratio of the feeding action of a plurality of feed dogs arranged in tandem, the length of the stitch produced may be instantaneously brought about, at the will of the operator, while the machine is in operation.

Other objects, features and advantages of the invention will appear from the detailed description of an illustrative form of the invention which will now be given in relation to the accompanying drawings, in which:

Figure 1 is a side elevational view of an overedge sewing machine having the stitch-shortening mechanism of this invention incorporated therein, a portion of the machine being shown in section and parts of the machine being omitted and other parts being broken away for better illustration of still other parts;

Figure 2 is a front elevational view of the machine shown in Figure 1;

Figure 3 is a view partly in plan and partly in 7 section, illustrating parts beneath the work support of the machine, the looper and parts of operating devices being omitted for clearer illustration of other parts; Figure 4 is a perspective view illustrating the stitch-shortening mechanism and associated devices; and

Figure 5 is a perspective view of the variable driving connection for the feed rocker.

Referring now to the drawings wherein like reference numerals denote corresponding parts throughout the several views, I have illustrated therein an overedge sewing machine ID in which the invention is incorporated. The machine includes a frame comprising a base or support bed I l; a standard l2 and a needle head [3 that overhangs a work support plate l4 carried by the base. A- rotary drive shaft 15 is supported in the frame at an inclined acute angle with respect to the work support. One end of the drive shaft extends beyond the frame and is secured to a belt wheel l6 that is adapted to be connected to a suitable drive, such as an electric motor (not shown), for imparting rotation to the shaft. The other end of the shaft terminates in needle head I3 and is connected to an arrangement of devices I! within the needle head for translating rotary movement of the shaft into reciprocatory movement of a needle bar l8. A needle 20 is secured to the lower end of the needle bar. Directly above work support I4 is a presser foot 21 that is normally urged in the direction of the work support by a spring-loaded presser bar 22 slidable in the needle head and extending therebelow.

The drive shaft carries aplurality of spaced eccentrics, namely, eccentrics 23, 24, 25 and 26. It is to be borne in mind that a one-piece crank shaft may be used in lieu of straight shaft [5 and the eccentrics carried thereby. Eccentrics 23, and are engaged by the upper strap members of corresponding pitman. connectors 2?, 28, 2t and 313, respectively. A reservoir 3| in the upper portion of the frame is adapted to contaill a supply of lubricant, such as a suitable oil 52, which is delivered to the connections formed by the eccentrics and corresponding pitnran straps by tubular devices 33 that contain wicking 3%.

A trimming blade 35, for trimming, a piece of Work that is stitched by the machine in advance of the point of entry of needle 2c in the work, is attached to one end of a lever 3b; This lever is pivoted. at its other end to the frame, as indi:-- cated at El, and is connected intermediate its ends to the lower strap of pitman 21.

An und'erlooper ti! and an overl'ooper d'l' (Figure 1) cooperate with needle 20 in the formation of stitches in the piece of work. Pitman 28 coacts withdevices (not shown) to operate underlooper Ed. Pitman 2'9, in turn, coacts with. other devices, also not shown, to operate overedge looper 4i The work to be stitched. is fed to the stitchforming devices by a feeding mechanism that will now be described. This'mechanism includes a main feed dog 43 and an auxiliary feed dog 4'4, both of which are carriedlby a main feed bar that is generally indicated by numeral 45 (Figures 3 and l). The main feed bar comprises an arm it that is attached at one end to a feed. rocker d1 which is rockable aboutashaft 48 that is carried in a lug integral with the base of the machine. Attached to the other end of arm 46 is a first block A second block 5!. is. supported inspaced relation to block 58 by a plate 52' which is fastened. to. block by screws 53- and to block 5! by screws it (Figure 3). Plate. 52 has a. slot 55. Block M carries a bracket 55- to which. main feed dog it is attached by a, screw 51.

Blocks 5t and it are provided with aligned bearing sleeves ti] and 6!, respectively. which support a reciprocable cylindrical rod 62. Auxiliary' feed dog M is affixed by a screw 63 to an extension M of rod Thus, it will be observedtha-trod 52 constitutes the feed bar for auxiliary feed dog Mi.- blocks 56 and bi, is an additional block which has apair of set screws These screws permit of ready adjustment of block alongthe auxiliary feed bar. An arm El projects beyond. one side of block E35 and registers with slot 55. This arrangement permits longitudinal movement ofv rod 62 and auxiliary feed dog M, but prevents an.- gular movement of these parts about the axis of rod 6'2. Attached to and. extending beyond the opposite side of block 65 is a pin 68 that is piv' otally connected to a driving link 69 for actuating rod t2 and, therefore, auxiliary feed dog 44. Link 69 carries a stud bolt "m that extends through' an arcuate-slotl I- in a bracket 12 which isattached to feed rocker 4-! by screws 13. A nut it secures a washer 15 to stud bolt 10. Washer '85 has a bent over extension 1-5 that projects into slot 'H- and serves to prevent rota tion of the stud bolt.

As is best: shown in Fi ure 5-, feed rocker 51 has a forwardly projecting arm :6 that is" pivotally connected to the lower end of a link Tl by a bolt it. This link hasaforked upper portion 8t for the reception of an arm 6 1 of a rock Mounted on. rod $2, intermediate 4 1 bracket 82. Arm Bl has an arcuate slot 83 through which a bolt 34 carried by forked link portion 39 is adapted to pass. Bracket 82 is rockable about a shaft 85 that is supported in a machine base lug 8% (Figure 3) and is restrained against movement to the left along the shaft, as viewed Figure 5, by a collar 81 that is affixed to the shaft by set screws 88.

Rock bracket 82 has an integral extension 98 that is spaced from the body thereof and defines a slot s l therewith. A pin 92, threaded at its inner end, extends through extension 96 and is secured thereto by a nut 93 which is disposed in: slot 9.! Pin- 92- carries a ball connector 94 that" is engaged by a strap 95 at the lower end of pitman 3B (Figure 1). This pitman, by virtue of its interconnection with eccentric 26 and ball connector 94, imparts rocking movement to bracket 82 about shaft 85' in response to rotation ofv drive shaft it. Also, inasmuch as feed rocker 4': is coupled to bracket 82 by arm 16 and link ll,. the feed rocker is rocked simultaneously with bracket 35 upon rotation of the drive shaft;

Referring to Figures I and 3', pitma'n 21 car'- ries a crank fit at its lower end. This crank is pivotally connected by a link 9'! to an arm 98" that is secured to block 51. Eccentric 2'3, pitman 2?, crank 96, link 97 and arm 98' constitute connections for imparting lifting and lowering movements to main feed bar 45 and therefore to" bothfeed dogs 33 and 4- 3 in response to rotation of drive shaft 55.

Earlier described parts, including eccentric 226, pitman 39, ball connector 9 rock bracket 82, operating member 'i'l' feed rocker 47, arm 46 and" associated devices constitute cooperating connections for imparting feed and return movements to feed dogs :33 and i s in response to rotation of the drive shaft. Thus, rotation of the drive shaft simultaneously imparts lifting and lowering movements and feed and return movements to thefe'ed' dogs.

The invention includes an arrangement of devices for shifting bolt 8 to the left as viewed in Figures 4 and 5, along slot 83, whereby to correspondingly tilt member IT about the axis of bolt T8 and decrease the movement of? feed rocker 4'! and thereby shorten the length of stitches formed by the stitch-forming devices at will during the operation of the machine". These devices comprise alinkage, includingv a link Hi8 that is engaged at. one end by bolt 84 and is clamped thereby to forked portion 80 of member 11. Link I00 is pivoted at its other end, as indicated at I'M,- to an arm H12. This arm issecured to and rockable with a shaft [03 that is rotatably supported in a lug I04 carried by the machine base. Another arm H15 engages a threaded extension MB of shaft I03 and is afiixed thereto by nuts I01. Arm W5, as in the case of arm I02, is rockable with shaft I03 and is pivoted at [138 to an upstanding link I09". Link- I09 has a pivot pin H0 that is connected to an end of an. arm IH that is secured to the inner endof. a. shaft H2 which is mounted for rotation in a machlnebase. lug H3 (Figure 39 Mounted. onthe inner end of shaft 2 is a: coil. spring H4; One endof the spring engages arm ill and theother end bears against the mach-inc frame in a manner to normally and yi'eldingly urge: arm Ill and shaft H22 in a counter c'lockwise direction, as viewed in Figure 4. An operating lever H5 is secured to the: outer: end of shaft H2 through the medium of a threaded shaft. eatension lift" and apair' of nuts- Hf.- This lever is connected to 9, depending chain I I8 that is adapti edv to be attached to a knee press pad or foot treadle (not shown). A bracket I is affixed to the machine base by a screw I2I. This bracket has a-vertical slot I22. I A pair of spaced stop pins I23 and I24 register with slot I22and'are vertically adjustable as allowedby the extremities of the slot.

For the purpose of briefly outlining the operation of'rthe machine, it is first assumed that the parts are assembled and are in the relative position shownin the drawings. With the parts in such position, operating lever H5, due to the action of spring H4, is in its normal position, i. 'e., it bears against upper stop pin I23 (Figure 4). Also, bolt 84 is disposed in the righthand end of slot 83 due to the connection of this bolt with lever I I5 through the intermediary of link I00, arm I02. shaft I03, arm I05, link I09,'arm III and shaft. I I2. As a consequence, member I! is so positioned that the feed dogs'operate in a manner that the stitch-forming devices will make the longest stitches for which the machine is set.

When the machine is placed in service, rotation of drive shaft I5 and eccentrics 23 and 26 actuates pitmans 21 and 30 to simultaneously impart lifting and lowering movements and feed and return movements to the feed dogs 43 and 44. While both feed dogs are carried by arm 46 and associated devices and are subject to the action of feed rocker 41, they are so arranged as to result in a differential feed action in relation to each other.

At such times as it may be desirable to shorten the stitch lengths, the operator, while the machine is in service, merely actuates the knee press pad or foot treadle, as the case may be, thereby pulling'downwardly on chain II8. This causes lever II5 to swing downwardly and shaft II2 to move in a clockwise direction, as viewed in Figure 1, thereby raising arm I I I and actuating link I09, arm I05, shaft I03, arm I02 and link I00 in a manner to shift bolt 84 toward the left along slot 83., This correspondingly swings member 11 toward the left, as viewed in Figures 1 and 5. This decreases the extent of movement of feed rocker 41 and as a consequence shortens the feed of both feed dogs and the length of stitches formed by the stitch-forming devices. The parts are so arranged and connected that the differential ratio between the feed dogs is constant regardless 'of'the length of stitches formed by the machine.

Thus it will be seen that the construction herein shown and described is well adapted to accomplish the objects of the present invention. It will be understood, however, that the invention may be embodied otherwise than as here shown, and that in the form illustrated certain obvious changes in construction may be made. Therefore, I do not wish to be limited precisely to the construction herein shown except as may be required by the appended claims considered with reference to the prior art.

I claim:

1. In a sewing machine having a rotary drive shaft and stitch-forming devices driven therefrom, the combination of work-feeding means comprising a plurality of feed dogs, first connections from said shaft for simultaneously imparting lifting and lowering movements to said feed dogs, second connections from said shaft for imparting feed and return movements to said feed dogs, a feed rocker common to said first and second connections, said second connections iii'-,j

eluding a device rockable in response to rotation of'said shaft, said feed rocker and device being ation of the machine for varying the extent of movement of said feed rocker.

2. In a sewing machine having a rotary drive shaft and stitch-forming devices driven therefrom, the combination of work-feeding means comprising a plurality of feed dogs, first connections from said shaft for simultaneously imparting lifting and lowering movement to said feed 1 dogs, second connections from said shaft for im-' parting feed and return movements to said feed dogs, a'feed rocker common to said first and second connections, said second connections including a device rockable in response to rotation of said shaft, said feed rocker and devices being rockable about different axes, and means connecting said feed rocker with each of said feed ment of the several feed dogs, and means interposed in the connections between said shaft and said feed rocker operable at will during the operation of the machine for varying the extent of movement of said feed rocker.

3. In a sewing machine having a rotary drive shaft and stitch-forming devices driven therefrom, the combination of work-feeding means comprising a plurality of feed dogs, first means connectedto and operable in response to rotation of said shaft for imparting lifting and lowering movements to said feed dogs, second means connected to and operable in response to rotation of said shaft for imparting feed and return movements to said feed dogs, said second means including a feed rocker and a rocker bracket that are rockable about different axes, a link connecting said feed rocker with said rocker bracket, and connections separately connecting said feed rocker with each of said feed dogs, said connections enabling different feed and return movements to be imparted to the several feed dogs,-'and means interposed between said feed rocker and said rocker bracket operable at will during the operation of the machine for varying the extent of movement of said feed rocker.

4. Ina sewing machine having a rotary drive shaft and stitch-forming devices driven therefrom, the combination of work-feeding means comprising a plurality of feed dogs, first means including a feed rocker connected to and operable in response to rotation of said shaft for imparting lifting and lowering movements to said feed dogs, second means connected to and operable in response to rotation of said shaft for imparting feed and return movements to said feed dogs, said second means including said feed rocker and a rocker bracket that are rockable about different axes, and connections separately connecting said feed rocker with each of said feed dogs, said connections enabling different feed and return movements to be imparted to the several feed dogs, and means comprising a linkage interposed between said feed rocker and said rocker bracket operable at will during the operation of the machine for varying the: extent of movement of said feed. rocker.

5. In a sewing machine having a rotary drive shaft and stitch-forming devices driven therefrom, the combination of workieeding means comprising a plurality of feed dogs, first means including a feed rocker connected to and operable in response to rotation of said shaft for imparting lifting and lowering movements to said feed dogs, second means connected to and operable in response to rotation of said shaft for imparting feed and return movements to said feed dogs, said second means including said feed rocker and a rocker bracket that are rockable about different axes, and connections separately connecting said feed rocker with each of said feed dogs, said connections enabling different feed and return movements to be imparted to the several feed dogs, and means interposed between said feed rocker and said rocker bracket operable at will during the operation of the machine for varying the extent of movement of said feed rocker, said last named means comprising a link having one end pivotally connected to said feed rocker and its other end shiftably connected to said rocker bracket.

6. In a sewing machine having a rotary drive shaft and stitch-forming devices driven thererom, the combination of work-feeding means comprising a plurality of feed dogs, first means including a feed rocker connected to and operable in response to rotation. of said shaft for imparting lifting and lowering movements to said feed dogs, second means connected to and operable in response to rotation of said shaft for imparting feed and return movements to said feed dogs, said second means including said feed rocker and a rocker bracket that are rockable about different axes, and connections separately connecting said feed rocker with each of said feed dogs, said connection enabling different feed and return movements to be imparted to the several feed dogs, a link having one end pivotally connected to said feed rocker and its other end shiftably connected to said rocker bracket, and a linkage coupled to said link and operable at will during the operation of the machine for shifting said other end of said link relative to said rocker bracket to correspondingly vary the extent of movement of said feed rocker.

7. In a sewing machine having a rotary drive shaft and stitch-forming devices driven therefrom, the combination of work-feeding means comprising a plurality of feed dogs, first means including a: feed rocker connected toand operable in response to rotation of said shaft for impartinglifting and lowering movements to said; feed dogs, second means connected toand operable in re.- sponse to rotation of said shaft for imparting feed and return movements to said feed dogs, said second means including said feed rocker and a bracket member that are rockable about difierent' axes, a link member pivotally connected at one end to said feed rocker, one of said members having a slot formed therein, the other of said members being coupled to and shiftable. along said slot in said one of said members, and connections separately connecting said feed rocker with each of said feed dogs, said connections en-- abl'ing different feed and return movements to be imparted to the several feed dogs, and means secured to said link member and operable at will during the operation of the machine for shifting said link member relative to said bracket memher to correspondingly vary the extent of movement of said feed rocker.

8. In a sewing machine having a rotary drive shaft and stitch-forming devices driven therefrom, the combination of work-feeding means comprising a plurality of feed dogs, first means including a feed rocker connected to and operable in response to rotation of said shaft for imparting lifting and lowering movements to said feed dogs, second means connected to and operable in response to rotation of said shaft for impartfeed and return movements to said feed dogs, said. second means including said feed rocker and a feed bracket that are rockable about different axes, said feed bracket having a slot formed therein, a link having one end pivotally connected to the feed rocker and its other end coupled to and s-hiftable along said slot in said fee-cl bracket, and connections separately connecting said feed rocker With each of said feed dogs, said connections enabling different feed and return movements to be imparted to the several feed dogs, and means comprising a linkage connected to said link and operable at will during the operation of the machine for shifting said other end of said link along said slot to correspondingly vary the extent of movement of said feed rocker ROBERT A. EARS.

Name Date Sauer July 30, 1935 Number 

